1. Field of the Invention
The present invention relates generally to modems and, more particularly, to modem training protocols for use by modems in point of sale terminals.
2. Related Art
Today, point of sale (“POS”) terminals are in use by various merchants throughout the country and enable convenient replacements for cash transactions. The POS terminals have become the preferred way of processing credit cards, debit cards, checks, smart chip cards, electronic benefits transfer, and other electronically submitted transactions in a traditional retail environment. The POS terminals are typically used in face-to-face transactions, where merchants swipe the customers' cards through the POS terminal or key-in payment information into the POS terminal. In turn, the POS terminal uses a POS modem to establish a connection with a service provider modem coupled to a financial service provider computer. The POS modem transmits the card information, transaction amount, etc. and receives an acceptance or rejection of the requested transaction from the financial service provider computer via the service provider modem.
FIG. 1 illustrates conventional POS system 100 including POS terminal 110, where POS terminal 110 includes POS modem 115 coupled to communication line 117, such as a telephone line. As shown, communication line 117 passes through communication network 119, such as the Public Switched Telephone Network (“PSTN”), which can provide a communication link between POS modem 115 and service provider modem 120. As further shown in FIG. 1, service provider modem 120 is in communication with service provider computer 125, such as a computer used by financial institutions for processing financial transactions.
As briefly discussed above, POS terminal 110 is capable of receiving the transaction amount and the card information, such as credit card number, expiration date, name, etc., and is further capable of transmitting the same data using POS modem 115 to service provider modem 120. At the other end, service provider modem 120 provides such data to service provider computer 125 for determining whether the requested transaction may take place. After service provider computer 124 makes such determination, service provider's acceptance or rejection of the requested transaction is transmitted to POS modem 115 via service provider modem 120.
In the past, due to the small amount of data that was needed to be transferred between POS modem 115 and service provider modem 120 (such data as the transaction amount, the card information, e.g. credit card number, expiration date, name, etc., which require a small number of data bytes), low speed modems running at 300–2400 bits-per-second (bps) were successfully utilized for processing POS transactions. Also, in order to further reduce the communication time between POS modem 115 and service provider modem 120, the standard modem training schemes, such as FSK (V.21, V.23 and Bell 103), PSK (V.22 and Bell 212A) and QAM (V.22bis) have been modified to shorten such modem training schemes for particular use in POS system 100.
For example, according to one FSK training scheme, POS modem 115 detects answer tone (2100 Hz or 2225 Hz) for only about 100 ms before starting to send FSK idle marks. While transmitting the FSK idle marks, POS modem 115 must be able to detect (1) no signal (quiet line), (2) PSK carrier, or (3) answer tone. POS modem 115 receiver must also be able to synchronize with FSK idle marks from service provider modem 120 within 100 ms after such FSK idle marks are present. Subsequently, POS modem 115 and service provider modem 120 enter data mode to receive and transmit data. Accordingly, as understood by those skilled in the art, the FSK training scheme is substantially reduced in time.
As POS systems have evolved, more and more data need to be communicated between POS modem 115 and service provider modem 120 and, thus, low-speed communication at 300 bps–2400 bps causes too much delay even if the training time is substantially reduced, since the data is still transferred at low speeds. For example, today, images and coupons may be sent from service provider modem 120, which require a substantial amount of data to be transferred from service provider modem 120 to POS modem 115. As a result, special attention has been focused on the use of faster data rates to transfer data between POS modem 115 and service provider modem 120. However, because faster data rates require substantially longer training time, use of faster data rates has not been viewed as an optimistic replacement for the existing low-speed POS terminals in the industry.
In a recent move to use faster data rates for POS terminals, one camp has set forth a modified V.29 training scheme, which shortens the V.29 training scheme. V.29 is an ITU standard (1976), which is a half-duplex facsimile scheme that can support speeds of 4,800 bps, 7,200 bps and 9,600 bps using QAM modulation, and has been adapted for Group 3 facsimile transmission over dial-up lines. However, the modified V.29 training scheme has many shortcomings. For example, the training time for the modified V.29 training scheme may take about 1–2 seconds. Further, the modified V.29 scheme is limited to a maximum data rate of 9,600 bps, which is still too slow and time consuming for transferring large amounts of data. Even more, the modified V.29 training only supports a half-duplex data mode.
Therefore, there is an intense need in the art for a high-speed data communications protocol designed to satisfy the requirements of the present and evolving POS systems, and which can provide fast training time, speeds of greater than 9,600 bps, full-duplex operations, and more.